MANKATO, Minn. — The Vikings are pivoting toward game preparation and management with their first preseason match against the Oakland Raiders looming in three days.

Coach Mike Zimmer is reviewing game tapes and drilling with general manager Rick Spielman on harried sideline decisions such as when to take timeouts, challenge calls and judge whether to attempt field goals or go for it on fourth down.

Assistant coaches have begun scheming some for the Raiders, beginning at 5 p.m. (PDT) Friday night at TCF Bank Stadium. But the focus remains internal, specifically, how quickly the Vikings are implementing wholesale changes to both the offense and defense.

Chase Baker, a former Paradise resident and second-year defensive tackle in Minnesota, continues to try and work his way into the rotation behind expected starters Linval Joseph and Sharrif Floyd. The Boise State product, who once played AAU basketball with Paradise High grad and Philadelphia Eagles receiver Jeff Maehl, made four tackles — two solo — in four games in 2013.

"This is about us getting better and evaluating us against other guys," Zimmer said Saturday. "I don't want to go out there and trick the Raiders. I want to go out and play solid fundamental football where the guys aren't thinking and their athletic ability doesn't show up."

Zimmer has a sense of how much he wants his first-team units on the field against Oakland. Preseason openers typically include a handful of series for starters, who ramp up their workload in games two and three.

It is a perennial balancing act to prepare the team without exposing it to injury in meaningless exhibitions.

"It could change based on how we practice the next few days," Zimmer said. "It's not going to be one, two, three and out."

The Vikings had their marquee practice Saturday night at Blakeslee Stadium. Their secondary remains banged up, with two players out with hamstring injuries.

Safety Robert Blanton is out indefinitely. Cornerback Josh Robinson, though, could return to practice Monday.

"He probably could (have gone Saturday),'' Zimmer said. "We're going to hold him out, and he should be good to go next week."

Also, tight end A.C. Leonard was sidelined Saturday night with a head injury and linebacker Brandon Watts was out with an undisclosed ailment.

The Vikings are off Sunday and have three days of practice next week before playing the Raiders.

Assessing the first seven practices, Zimmer was pleased with some areas, disappointed in others, forcing him to recalibrate expectations.

"I'm not happy but probably satisfied with the progress we've made so far," he said. "Offensively, I anticipated us aligning not as well as we've been. We've done a really good job there. I think we're blocking the run pretty good. I think we've got to get better in our pass protection right now.

"Defensively, kind of the opposite. I thought we'd line up a little bit better. They're getting a lot of movement. I thought we'd be a lot more precise in our alignments than we've been. And we're probably ahead (more) in the blitz packages than I thought we'd be."